One of the great intrigues of "Weeds" is also one of its biggest worries. When a show takes so many chances - some fans might say recklessly - when does it all implode? When does the creative risk become less rewarding and instead become annoying, or even detrimental?

Season 4 of the beloved Showtime series almost predictably ratchets up the chance taking, but the first three episodes are just as rich and compelling and funny and conflicted as any that have come before it. Whether Season 4 can continue to pull this off remains to be seen, but you have to give creator Jenji Kohan some credit for her fearlessness. Each season she has spun more plates than is reasonably wise and lived to see a clean floor and a content audience through it all.

But now she's onto something completely different (though not entirely unexpected given the show's history). When last we saw Nancy Botwin (Mary-Louise Parker), the accidental pot-selling suburban mom, she had just poured gasoline on the furniture in her mini McMansion in Agrestic, the fictional suburban enclave of SUVs, minivans, clean lawns, good schools and a whole underbelly of upper-middle-class dysfunction. As she torched the house, just ahead of the advancing Southern California firestorms about to engulf Agrestic anyway, she sped away on a Segway with a wry smile on her face.

The arson would, perhaps, hide the fact that she was running an enormous grow house, that her small-time pot selling - which she started almost out of necessity when her husband died while jogging - was now a full-grown business. She wasn't just selling bags to disaffected suburban soccer moms anymore, she was a drug dealer, plain and simple.

The trouble with burning down the house, of course, is that three seasons of suburban satire went up in smoke. Season 4 starts with big, if obvious, change. There is no more Agrestic. (In fact, you're likely to hear the Malvina Reynolds classic theme song, "Little Boxes," only in the first episode.) Now Nancy, Silas (Hunter Parrish), Shane (Alexander Gould) and Andy (Justin Kirk), are on the run, heading south toward the Mexican border. Gone, with barely a mention, are Conrad (Romany Malco) and Heylia (Tonye Patano), Nancy's former partner-lover and pot provider, respectively.

As jarring as their omission is, that pales in comparison to the bigger picture: "Weeds" is now a different show entirely.

Big change

Kohan and her writers have effectively changed the premise, if not entirely, then certainly extremely. Not only has Nancy left Agrestic, she has willingly become a bigger player in the drug business and has - continuing a theme from Season 3 - seen her two sons become inescapably mired in her dealings. This is no small gamble. Many viewers do not like change. And though "Weeds" is still joyously, rebelliously "Weeds," the look and feel and sound of the show are different.

More important, the conceit of the original premise is now long gone: that Nancy, perhaps naively, perhaps coming into her own sense of devilish purpose, kept her family intact in the wake of her husband's death by selling a little pot on the side, to the wacky, hypocritical and judgmental suburbanites living in Agrestic.

Most people went with that premise - moral qualms be damned - because Agrestic's hidden truths and Nancy's pragmatism (and charm in the process) were the essence of the show. That began to change as she evolved through Seasons 2 and 3, of course, but it wasn't until the latter parts of Season 3, when Nancy was really faced with how she had made her sons complicit in her life of crime, that it all hit home for her. And the fact that Parker was able to make you love her adorable snarkiness through it all was really something, especially when it was clear she had gone down an ever more dangerous, less naive path. That was the drama inherent in the series, offset as it was, by the antics of Andy and Doug (Kevin Nealon), who provided much of the bumbling comic relief.

But now? There's no trace of naivety in Nancy. She wants to be a bigger drug dealer. Her family is along for the ride. Will this change her (and the show) in the eyes of viewers? Will making statements about border policy, immigration, etc., seem more patently easy (and less fun) than watching Nancy tweak the stuffy sensibilities of Celia (Elizabeth Perkins) and her kind?

So far, not really. "Weeds" still feels very familiar and fresh. Though it's unsettling to see Conrad and Heylia dismissed so easily, the series scored an enormous coup in getting Albert Brooks to play Andy's father, Lenny Botwin. Brooks is exceptional in the first three episodes - and not just his usual, funny self. Lenny has fewer insecurities and nervous tics than many of the characters Brooks has written and played before. He's more seriously dramatic here but also scathingly funny as the gambling, vindictive, reproachful father.

It might not be too early to start thinking about an Emmy nomination for Brooks.

Everyone else is in fine form as well. That Parker makes this role seem so effortless is a real testament to her talent. Her burden this season will be to make the audience have a reason to care for Nancy, to pull for her. Kirk has always leavened the series with much-needed wit and even philosophy, while Nealon continues to be wonderful as stoner Doug and Perkins gets new material as the ever-more-put-upon Celia.

Just when you think "Weeds" is going to flame out - like Agrestic - it survives what seems certain catastrophe. To keep throwing this warning into the air season after season will also have to end. Kohan and her writers deserve perhaps more credit than they're getting for forcing change and making it artistically compelling.